On a Sunday morning in May, a paranoid man walked up to the Glendale police headquarters and began asking a slew of questions. "I know this is gonna sound crazy, but I feel like there are people following me. I feel like there was a chopper -- do you hear a chopper?" the man asked, suspicion seeping through his voice. Informed by an officer that police in the L.A. suburb were not flying any helicopters, he began to waver. "So it's not yours. Do you hear one? I could be nuts."

So began an odd yet polite 11-minute conversation in which then-Deutsche Bank managing director Brian Mulligan, 53, discussed his snorting of bath salts, the addictive and illegal drug that causes feelings of euphoria but also violent delusions. He said he had taken the drug about 20 times and asked, "How long does this stuff stay in your f--ing system?" The officer who spoke with Mulligan had a stern warning: "You need to get on top of this before it gets on top of you."

Only a few days later, Mulligan had another run-in with officers -- and this time, the interaction wasn't so cordial. At about 1 a.m. on May 16, Los Angeles Police Department patrol officers discovered the married father of two trying to break into cars in a shabby residential neighborhood in the Highland Park area, according to an LAPD account. When they approached him, he snarled, bared his teeth and attempted to hit an officer. Another officer struck Mulligan with a baton, but Mulligan continued to kick and punch one of the officers until he was placed in an immobilizing restraint and handcuffed. How Mulligan wound up in Highland Park and in a scrape with the LAPD remains murky -- though a lawsuit his attorney plans to file should begin to shed light on the affair -- but what is clear is that the 6-foot-tall Mulligan was no match for the three police officers. His face was battered and bloodied, as revealed in gruesome photographs splashed on TMZ, and his nose was broken in 15 places, requiring emergency surgery (and 54 stitches) at nearby Huntington Memorial Hospital. Only after recent surgery could Mulligan breathe properly.

Although the incident made headlines during the summer, the full extent of Mulligan's Hollywood background never emerged. Once an executive who served as co-chairman of Universal Pictures with Stacey Snider, Mulligan -- who had pulled down as much as $4 million a year as CFO of Seagram during the late 1990s -- cut deals for Edgar Bronfman Jr. and arranged financing for MGM and Spyglass Entertainment. He gunned for Barry Diller's job when the mogul ran Vivendi Universal Entertainment in the early 2000s and was named by Premiere magazine as one of the 50 most powerful people in Hollywood. In addition to an eight-year stint at Universal, Mulligan also served as Fox Television chairman in 2001. For the past three years, he had been a vice chairman at Deutsche Bank, covering media finance, acquisitions and IPOs, working from the company's 41st-floor offices at downtown's One California Plaza. Married to Victoria, a homemaker and part-time paralegal, and the father of a high school football star son and a college-age daughter, he long has resided in tony La Canada-Flintridge near Pasadena, golfs at Annandale Golf Club and is well regarded in Pasadena society circles. Says Snider, now co-chairman and CEO of DreamWorks Studios, "There couldn't be anyone about whom a story like this would shock me more."

Just days after his Dec. 6 surgery, Mulligan gave his first interview since the May incident, telling THR about his road to recovery and his next moves now that he has parted with Deutsche Bank. "I am relieved that the bulk of my physical injuries have been dealt with, and I've already been contacted for advisory work," says Mulligan. He declined to discuss specifics from the fateful night in May, leaving plenty of questions that could be answered in a coming legal battle over his treatment.

Mulligan filed a $50 million claim against the LAPD in August, but it was rejected in September (such a claim typically is a precursor to a lawsuit). Now, his lawyer, Skip Miller, is planning to sue the city of Los Angeles in early January for what is likely to be tens of millions of dollars in damages stemming from the incident. "This is going to be a jury trial in federal court for violation of his civil rights -- for beating him to a pulp for absolutely no reason," says Miller. The LAPD declined comment, referring THR to a news release that detailed the May 16 incident.

Muddying the waters is Mulligan's admitted use of bath salts, a powerful designer drug that LAPD officer and narcotics expert Cecil Mangrum says has some of the effects of LSD, cocaine, methamphetamines and PCP rolled into one stimulant that can be snorted, smoked, swallowed or injected -- and makes some people uncontrollably violent. "It's an evil combination of everything," Mangrum says.

John McAfee, the technology multimillionaire who founded software company McAfee Inc. and is now a person of interest in the killing of a neighbor, has discussed his use of bath salts -- crystals that resemble legal bathing products such as Epsom salts -- saying on an Internet forum, "It's the finest drug ever conceived," in part for "the indescribable hypersexuality." Because the drug has gained a toehold only in the past few years, cities have had to move swiftly to combat it. Los Angeles adopted a law in October 2011 that made it illegal to use or sell the drug. And in July -- a few months after the Mulligan incident -- President Obamasigned a federal ban on the drug. Meanwhile, Mulligan's apparent transformation has transfixed Hollywood. "He was the most taciturn bean-counter ever," one former high-level Universal executive says. "What happened to him? It's scary."

Speaking out for the first time, Mulligan's wife, Victoria, doesn't doubt her husband, even though she is aware of his struggle with bath salts. "To have something happen like this is a living nightmare for all of us," she says, declining to discuss the May incidents. "But my husband perseveres -- and always comes out on top -- and he deserves it. He is a good guy."